Core-level and valence-band electronic states of Bi2Sr2Cal sbnd xYxCu2Oy studied by photoemission

Core-level and valence-bond electronic structures of Bi2Sr2Ca1 sbnd xYxCu2Oy (x=0, 0.4, and 0.7) have been studied by X-ray and UV photoemission spectroscopy. A Fermi edge is observed for x=0.4 as well as for x=0. It is found that the density of states at the Fermi level and the intensity of a 1.2-eV peak are reduced but the binding energies of Bi 5d are not changed by substitution of Y for Ca. The origin of the states and the structure is discussed in terms of 02p bands mainly in the Cu sbnd O layers.